1 // Copyright (C) 2001-2003
2 // Mac Murrett
3 //
4 // Distributed under the Boost Software License, Version 1.0. (See
5 // accompanying file LICENSE_1_0.txt or copy at
6 // http://www.boost.org/LICENSE_1_0.txt)
7 //
8 // See http://www.boost.org for most recent version including documentation.
9 
10 #ifndef BOOST_SINGLETON_MJM012402_HPP
11 #define BOOST_SINGLETON_MJM012402_HPP
12 
13 #include <boost/thread/detail/config.hpp>
14 
15 namespace boost {
16 namespace detail {
17 namespace thread {
18 
19 // class singleton has the same goal as all singletons: create one instance of
20 // a class on demand, then dish it out as requested.
21 
22 template <class T>
23 class singleton : private T
24 {
25 private:
26     singleton();
27     ~singleton();
28 
29 public:
30     static T &instance();
31 };
32 
33 
34 template <class T>
singleton()35 inline singleton<T>::singleton()
36 {
37     /* no-op */
38 }
39 
40 template <class T>
~singleton()41 inline singleton<T>::~singleton()
42 {
43     /* no-op */
44 }
45 
46 template <class T>
instance()47 /*static*/ T &singleton<T>::instance()
48 {
49     // function-local static to force this to work correctly at static
50     // initialization time.
51     static singleton<T> s_oT;
52     return(s_oT);
53 }
54 
55 } // namespace thread
56 } // namespace detail
57 } // namespace boost
58 
59 #endif // BOOST_SINGLETON_MJM012402_HPP
60